Most patients suffering from chronic colitis, constipation, intestinal disorders and other gastrointestinal diseases are not suitable to eat pure milk. Clinically, patients often complain that they are prone to bloating, diarrhea, or alternating bloating and constipation after taking pure milk, and some patients show stubborn constipation. This is because the digestion and absorption of milk requires the participation of enzymes in the body, and patients with poor gastrointestinal function generally have poor enzyme activity, so it is not easy to digest and absorb milk, and some abdominal distension, intestinal tinnitus and other uncomfortable reactions, and even diarrhea and constipation will occur; some patients belong to allergic body, after taking milk, because of allergic allergic reaction, and manifest diarrhea, alternating diarrhea and constipation, or constipation. Therefore, it is recommended that patients with poor gastrointestinal function should pay attention to the reaction after taking milk, and if symptoms related to milk consumption do occur, they should eat less milk, especially pure milk. Some patients have adverse reactions to plain milk but can adapt to yogurt and can take yogurt instead.